Electrically operated fastener driving tool



March 9, 1965 R. H. DoYLE E'rAl. l

ELECTRICALLY OPERATED FASTENER DRIVING Toor.

March 9, 1965 R. H. DoYLE ETAL- 3,172,121

ELECTRICALLY OPERATED FASTENER DRIVING TOOL 2 Sheets-Sheet 2 Filed April1, 1963 wwbm Num..

United States Patent O 3,172,121 ELECTREQALLY (BPERATED FASTENER BREWINGTL Richard H. Doyle, Mount Prospect, and Leroy N. Hermann, St. Charles,lll., assiguors to Fastener Corporation, Franklin Paris, lll., acorporation of illinois Filed Apr. 1, 1963, Ser. No. $19,427 o Claims.(Cl. 1--49) This invention relates to an electrically operated powerunit and, more particularly, to an electrically operated, portablefastener driving tool. This application is a continuation-in-part of acopending application of Richard Doyle et al., Serial No. 161,651, filedDecember 22, 1961, now Patent No. 3,141,171, issued July 21, 1964.

Pneumatically operated tools for driving fasteners, such as staples ornails, in a single power stroke have found extensive acceptance inindustrial and some building applications in which the number of toolsin use is large enough to justify the investment required for aircompressing facilities, either stationary or mobile. However, aconsiderable field of application remains in which power operatedfastener driving tools cannot be used because of the cost and difficultyof providing a suitably flexible system of supplying compressed air.

The virtually universal availability of electric power indicates thatmany of the factors limiting an expansion in the use of power operatedfastener driving tools could be overcome with electrically operatedfastener driving tools. A portable fastener driving tool operated byelectric power is shown in the above-identied application and in anothercopending application of Richard H. Doyle et al., Serial No. 161,727,filed December 22, 1961. ln the latter application, a winding foroperating a magnetic armature that actuates a fastener driving elementor blade is energized for no more than one cycle of an alternatingcurrent or undulating potential to provide a single power stroke duringwhich the fastener is driven. The heating to which the winding means andthe tool housing are subjected in a tool of this type is sharply reducedfrom that encountered in conventional electric tools because of the veryshort interval during which the winding means is energized. However,even with this improved type of tool, undesirable heating of thewinding, housing, and control components can occur in certainapplications.

Accordingly, one object of this invention is to provide a new andimproved electrically operated power unit. Y

Another object is to provide a new and improved electrically operatedtool for driving fasteners.

Another object is to provide an electrically operated fastener driving.tool including new and improved cooling means.

A further object is to provide a fastener driving tool in which fluidconveying means are formed adjacent an operating winding andin which airdisplacing means are actuated by the operation of a blade drivingarmature to move a cooling fluid through the fluid conveying means.

Another object is to provide an electrically operate` fastener drivingtoolv including new and improved means for mounting an operating windingin a cavity in a housing for the tool.

Another object is to provide a fastener driving tool including means formounting an operating winding in a ice tool housing to permit itsremoval for maintenance or replacement.

ln accordance with these and many other objects, an embodiment of theinvention comprises an electrically operated, portable fastener drivingtool including a housing having a forward or head portion and arearwardly extending hollow handle portion. The head portion includes acavity and is secured at its lower end to aL nosepiece assembly forminga drive track to which staples or other fasteners are successivelysupplied by a magazine assembly connected between the head portion andthe handle portion. A winding means having an axially extending openingis disposed in the lower end of the cavity with the axial openingaligned with the drive track. The winding means is supported in a spacedrelation to the adjacent wall of the cavity to provide one or aplurality of fluid conveying means that communicate both with theremainder of the cavity and with the atmosphere through ports or outletsformed in the housing.

A magnetic armature is slidably mounted in the axial opening in thewinding and is connected at its lower end to a fastener driving bladethat is slidably received within the drive track. Toe upper end of thearmature means is secured to an air displacing means that is slidablymounted in a cylindrical upper portion of the cavity. Thus, whenever thewinding means is energized to aetuate the armature, the air displacingmeans produces a flow of air 'through the fluid conveying means to coolthe winding. Further, the mounting of the winding means in a spacedposition from the housing prevents the direct transmission of heat from.the winding to the remaining components of the tool.

A control circuit for controlling the energizationof the winding meansis disposed in the hollow handle of the housing and includes a manuallyactuated switch which is operated whenever the tool is to be operated.ln one embodiment of the invention, the hollow handle is sealed off fromcommunication with the cavity in the head portion with a layer of heatinsulating material disposed between the housing and handle to reduceany heating of the handle occasioned by heat generated by, the windingmeans. ln another embodiment, the cavity in the head portion and theinterior of the hollow handle in which the control components aredisposed are placed in fluid cornmunication so that the actuation of theair displacing means in response to the operation of the tool produces aflow of coolingair through the hollow handle to cool the controlcomponents therein and to prevent excessive heating of the handleportion of the housing.

Many other objects and advantages of the present invention will becomeapparent from considering the following detailed description inconjunction with the drawings, in which:

FIG. 1 is a sectional View of an electrically operate-z fastener drivingtool embodying the present invention;

FlG. 2 is a fragmentary elevational view of a portion of the tool shownin FIG'. l

FIG. 3 isa sectional view taken along line 3 3 in FlG. l;

FIG. 4 is a fragmentary sectional view of an electrically operatedfastener driving tool forming a second embodiment of the invention;

FlG. 5 is a sectional view taken along line 5-5 in FIG. 4; and FIFIG. 6is a sectional view taken along line 6-6 in Referring nowmorespecifically to FIGS. 1-3 of the drawings, therein is disclosed anelectrically operated, portable fastener driving tool which is indicatedgenerally as 100 and which includes :a housing 102 having a forward orhead portion 102a and a rearwardly extending hollow handle 104. The headportion 102a defines a cavity 106 in lthe lower end of which is disposeda winding means 108 having an axially extending opening 110 in which isslidably mounted a magnetic armature 112. A fastener driving blade 114is secured to the lower end of the armature means 112 and is slidablyreceived within a drive track 116a formed in a nosepiece assembly 116that is carried on the lower end of the head portion 10211. A magazineassembly indicated generally as 118 which is connected between thenosepiece assembly 116 and a rearwardly and downwardly extending portion104C of the hollow handle 104 successively supplies fasteners, such asstaples, to the drive track 11601 to be driven by the fastener drivingblade 114.

The winding means 108 is selectively energized under the control of apower supply circuit 120, the operation of which is controlled by amanually actuated switch assembly indicated generally as 122. When theswitch assembly 122 is manually actuated, the power supply controlcircuit 120 energizes the winding 108 to drive the armature 112downwardly through a single power stroke during which the blade 114engages and drives the fastener supplied by the magazine assembly 118.The armature 112 and the blade 114 are returned to their normal positionby suitable return means. During both the downwardly directed powerstroke and the return of the armature 112 to its normal position, lanair displacing means in the upper portion of the cavity 106 forces airaround the winding and through the hollow handle 104 to cool the winding108 and the control components mounted in the handle 104.

Referring now more specically to the construction of the housing 102,this member is preferably formed of a nonmagnetic metal and includes theforward or head portion 102a dening the cavity 106. The lower end of thehead portion 102a is provided with a generally cylindrical opening 124in which is movably mounted a generally cylindrical structure 116bforming a part of the nosepiece assembly 116. The structure 116k isprovided with a transversely extending passageway 126 in communicationwith an enlarged portion in the drive track 116a to provide means forexhausting air entrapped below the armature 112 when it moves downwardlyduring a power stroke. A resilient bumper 128 for cushioning thetermination of the power stroke of the armature 112 is disposed within arecess 130 in the structure 116b.

The upper end of the head portion 102:1 is provided with an opening 132of a diameter at least as great as the winding means 108. The opening132 is closed by a removable closure cap 134 that is secured i-nposition by a plurality of threaded fasteners 136. The cap 134 includesa port or passageway 136 partially covered by a baffle 138 that placesthe upper end of the cavity 106 in communication with the atmosphere.

The winding means 108 consists of a plurality of turns of copper wireformed in a generally annular configuration to define the axial opening110 and having an outer surface that is tapered inwardly and downwardlyat its lower end. The winding means is covered or potted in a dielectricmaterial 140 that may be metal filled to facilitate the transmission ofheat from the winding 108. The lower end of the dielectric material 140is provided with a bossed portion 140a that is received within thecircular opening 124 in the lower end of the head portion 10211, and theupper end of the dielectric material 140 is provided with an upperbossed portion 140b. l To support the winding means 108 in a centrallydisposed position in the lower end of the cavity 106 spaced from thewalls of the head portion 102a so as to provide a generally annular airor fluid conveying space 142 surrounding the winding 108, the upperbossed portion 1401; is disposed within an inner opening 144 (FIG. 3) ina spider structure or means 146. The spider construction 146 i-ncludesan inner circular member 14611 connected to an outer circular member146b by a plurality of radially extending spokes 146C. A removablefastening means 148 comprising a resilient arc or ring seated in a slot150 inthe inner wall of the head portion 102:1 is disposed above andbears against the outer annular ring 146]) to detachably mount the`spider construction 146 and, thus, the winding means 108 in its desiredposition. When the locking means 148 and the spider 146 are removedafter removing the closure cap 134, the winding means 108 can be removedfrom the housing 102 through the top opening 132.

The fluid conveying means or space 142 surrounding the winding means 108provides means for moving a cooling fluid such as air, adjacent thewinding 108 to carry off heat generated by the operation of the tool100. The lower end of the space or tiuid conveying means 142 is placedin communication with the atmosphere by a plurality of ports orpassageways 152 formed in the lower end of the head portion 10211. Theupper end of the air conveying space 142 is placed in communication withthe lower end of the cavity 106 by a plurality of openings 154 formedbetween adjacent spokes 146e in the spider construction 146.

The wall `of the head portion 102e immediately adjacent the windingmeans 108 is provided with a vertical- 1y extending slot 156 extendingthroughout the length of the winding means 108 to prevent the portion ofthe electrically conductive housing 102 adjacent the winding 108 fromoperating as a shorted turn or lag coil. Without the slot 156, the partof the head portion 102a disposed adjacent the coil 108 would operate asa single electrically conductive turn which, when the energization ofthe winding means 108 is terminated at the end of a power stroke, wouldretard the collapse of the ilux field and delay the return of thearmature 112 to its normal position.

The armature means 112 is shown as comprising a single or integralcylindrical body of magnetic material, although it can be constructed ofa plurality of parts. The upper end of the fastener driving element orblade 114 is secured to a lower end of the armature 112 by atransversely extending pin 158. A washer or ring 160, preferably formedof Teflonj is carried on the lower end of the armature 112 to provide alow friction bearing surface between the wall of the axial opening andthe armature 112.

The upper end of the armature 112 is connected to fluid or airdisplacing means for circulating a cooling fluid through the space 142surrounding the winding means 108. More speciiically, this airdisplacing means is provided by a somewhat flexible and annular vane orpumping element 162 preferably formed of sheet metal which is mounted onthe armature 112 and biased into engagement with a flanged portion 11251on its upper end by a compression spring 164 interposed between theinner edge of the vane 162 and the junction of the inner Wall of thehead portion 102e and the upper surface of the locking means 148. Theouter circular edge of the element 162 carries a resilient sealingelement 166 that slidably engages the cylindrical upper portion of thecavity 106. The spring 164 not only biases the vane 162 against theflanged portion 112a of the armature 112 but also provides an armaturereturn means for normally biasing the upper end of the armature 112against an annular resilvient bumper or stop member 168 carried on theclosure cap 134.

When the armature 112 is moved downwardly against the action of thespring 164, the vane 162 moves downwardly to force air in the cavity 106downwardly through the fluid conveying means 142 and outwardly to theatmosphere through the ports 152, while drawing air into the upper endof the cavity 166 through the port or passageway 136. When the armatureis moved upwardly by the spring 164 at the end of the driving stroke,the corresponding movement of the air displacing means 162 draws coolingair into the cavity 166 through the conveying space 142 and the ports152 and discharges air from the upper end of the cavity 106 through thepassageway 136.

The control components, including the power supply unit 12@ and themanually actuated switching assembly 122, are mounted within a cavity170 formed by the hollow handle 1h41 and a recessed area or hollowformed in a rearwardly projecting portion 1Mb of the housing 102. Thehandle 1114 is preferably formed of one or ltwo pieces of a plasticmaterial, and its forward end is opened and provided with two forwardlyprojecting side walls 164e that are secured to the rearwardly projectingportion 1021) of the housing 162 by a plurality of threaded fasteners172. The power supply circuit 12d is mounted within the cavity 17d andcan be supported therein by a plurality of ribs or projecting portions1Mb formed integral with rthe hollow handle 1li/l. This circuit can beof a conventional design or one oi the improved circuits shown in thecopending application identified above. The control circuit 126 isprovided with power from a iline cord 17d which is adapted to beconnected to a conventional source of alternating current potential andwhich passes through a strain relief element 176 to be secured to theinput terminals of the control circuit 121). The control input terminalsof the circuit 121i are connected to the manually actuated switchingassembly 122, and the output terminals are connected to the winding 16Sby conductors which pass through an opening 17S in the housing 1112. Theopening 178 also places the cavity 17'@` in communication with thecavity 166 through the openings 154 in the spider structure 146.

The manually actuated switching assembly 122 includes an enclosed orsealed switch unit 169 having an operating plunger 162 that is adaptedto be engaged and operated by a plunger 13d-that is slidably mounted ina sleeve 186 carried on the rearwardly projecting portion 1612!: of thehousing. The plunger 134 is urged toward the operating plunger 182 by acompression spring 1S@ that is interposed at the head of the plunger 184and a stem 19@ which is also slidably mounted within the sleeve 136 andwhich is biased into engagement with the upper surface of a triggerelement 192 by a compression spring 194. The trigger 192 is pivotallymounted on a supporting bracket 196 by a pivot pin 197, the bracket 196being carried on the housing 1112.

rlhe handle 1M is also provided with the downwardly extending portion104C to which the rear end of the magazine assembly 113 is pivotallyconnected by a pivot pin 19d. Since the nosepiece structure 11619 isslidably mounted in the opening 12d in the housing 1652 and the rear endof the magazine assembly 118 is pivotally mounted on the shaft or pin19S, the magazine assembly 118 and the nosepiece construction 116 arecapable of a limited degree of pivotal movement relative to the housing162 to provide means for absorbing recoil forces produced when the tool1li@ is operated. The magazine assembly 116 is biased against thenosepiece construction 116]) by the force of a spring 19de actingbetween the pivot pin 19S and a bracket portion 198]). The rearwardlyextending portion 194e of the handle 1114 can also be provided with aport or opening 199 that connects the atmosphere to the cavity 176.Since Vthe cavity 171i communicates with the atmosphere through theopening 199 and vwith the cavity 166 through the opening 178, theoperation of the armature 112 and the consequent displacement of the airdisplacing means 162 produces a tlow of air through the cavity 171i tocool the handle 1li-i and the components therein.

When the tool is to be operated, the lower end of the nosepiece assembly116 is placed against the workpiece and the trigger 192 is pivoted in acounterclockwise direction about the shaft 197 to move the stem 196 andthe plungers 184 and 182 upwardly to actuate the sealed switch unit 180.T he switch unit 161B controls the power supply unit or circuit 121i sothat the winding means 103 is connected directly across the potentialsource supplied by the line cord 17d to energize the winding means 1138for a selected period of time such as a half cycle of an alternatingcurrent potential. When the winding 168 is energized, the armature 112moves downwardly against the action of the compression spring 16d sothat the lower end of the driver blade 112 engages and drives a fastenersupplied to the drive track 11651 by the magazine assembly 1155, thedownward movement of the armature 112 being terminated by engagementwith the resilient bumper 12S. During this downward movement, the vane162 moves downwardly within the cylindrical portion of the cavity 166 toforce the air entrapped below the vane downwardly through the airconveying space 142 and into the atmosphere through the ports 152.Similarly, a portion of the air disposed in the cavity 1116 below thevane 162 is forced through the opening 17S and the cavity 176 to beexpelled to the atmosphere through the port 199.

When the energization of the winding 163 is terminated, the compressionspring 164i moves the vane 162 and the armature 112 upwardly until theanged portion 112er at the upper end of the armature 112 engages theresilient stop means 16S. During this movement of the vane 162, ambientair from the atmosphere is drawn into the air conveying space 142through the ports 152 and into the cavity 17 il through the port 199.Thus, during each cycle of operation of the tool 11st), air is movedthrough the air conveying means 142 and the cavity 17@ to cool theWinding 1118 and the components of the control or power supply circuit120.

Whenever the control components in the cavity 176 require maintenance orreplacement, the magazine assembly 1153 is disconnected from the handle11M, and the threaded fasteners 172 are removed to permit the handle1114 to move rearwardly relative to the head portion 1412. When thehandle 1M is displaced, the control circuit 120 can be removed throughthe opening in the forward end of the handle 1M. In addition, the sealedswitch unit 18d and the operating mechanism therefor can be servicedthrough the rearwardly opening recess in the portion 16219 of thehousing 1192.

In the event that it becomes necessary to replace or repair any of thedrive components of the tool 161B, the threaded fasteners 136 can beremoved to permit the removal of the closure cap 11i/1. This permits theair displacing vane or pump element 162 to be removed through the topopening 132 of the housing 1112 together with the armature 112, thedrive blade 1141 and the compression spring 164. When the winding 108 isto be removed or replaced, the ends of the resilient locking member 146are moved inwardly toward each other unit until this element can bedisplaced from the groove 156 and removed through the top opening 132.The spider structure 146 and the winding means 168 can now be removedthrough the top opening 152.

When the winding means 1113 is replaced, the intertting engagement ofthe lower boss 146o with the circular opening 124 and the cooperation ofthe spider structure 146 with the inner wall of the head portion 162:1and the upper boss 146k insures that the winding means 16? is properlylocated spaced from the walls of the head portion 1112er to provide theair conveying space 142. The winding 161i is secured in its adjustedposition in which it is also properly aligned with the drive track 116eby snapping the fastening means 1h13 into the recess or groove 1511. Theremaining components can then be replaced through the top opening 132after which the closure cap 134 is secured in position by the threadedasterers 136.

FIGS. 4-6 of the drawings illustrate an electrically operated stapler ortacker 200 which embodies the present invention and which is similar tothe tool 100. The stapler 200 includes new and improved means forcooling the operating winding means in the stapler as well as novelmeans for insuring that the drive track of the stapler remains inengagement with a workpiece in spite of recoil. The tacker 200 comprisesa housing formed by a generally cylindrical head portion 202 to which issecured a separate and rearwardly extending handle 204. The tacker 200,which can be operated by the control means, described in theabove-identified copending applications, includes a winding means 206disposed in the housing l202 and having an axially extending opening 202in which is slidably disposed the lower end of a magnetic armature 210to which the upper end of a fastener driving blade 212 is secured by apin 213. The lower end of the driver blade 212 is slidably mounted in adrive track 214 formed in a nosepiece assembly 216. Suitable fasteners,such as staples or nails, are supplied to the drive track 214 by amagazine assembly, indicated generally as 210, which is rigidly securedto the nosepiece assembly 216 and which is pivotally mounted to a rearportion 204e! of the handle 204.

When the tool 200 is operated, as by the actuation of switch means (notshown) carried on the handle 204, the Winding 206 is energized to movethe armature 210 and the connected driver blade 212 downwardly so thatthe blade 212 engages and drives a fastener supplied by the magazineassembly 210. During this downward movement, a vane or air impellingmeans secured to the armature 210 draws ambient air into the interior ofthe housing 202 through openings in an upper portion thereof and forcesair downwardly around the outer surface of the winding 206 which isspaced from the housing 202. This air is discharged through openings inthe lower end of the housing 202.

To provide means for insuring that the nosepiece assembly 216 remains inengagement with the workpiece during the fastener driving operation, thepivoted connection of this assembly and the magazine assembly 218 to thehandle 204 is utilized. When the tool 200 is to be operated, thenosepiece assembly 216 is placed against the workpiece, and thiscomponent and the magazine assembly 218 are pivoted relative to theremainder of the tool. Thus, any recoil produced by the operation of thetool can be absorbed by displacing the housing 202 and the handle 204relative to the assemblies 216 and 218 which remain in position so thatthe nosepiece assembly 216 contacts the workpiece.

Referring now more specifically to the housing 202, this housing isgenerally cylindrical in form and preterably is fabricated from anonmagnetic material. The open upper end of the housing 202 is closed bya cover 220, and the open lower end of this housing is closed by anonmagnetic member 222. The winding 206, which is similar to the winding100 provided in the tool 100, is disposed in the lower end of thehousing 202 resting on a resilient element 224 that engages the lowerend of the armature 210 at the end of its power stroke to cushion thetermination of the power stroke, The winding 206 is secured in positionby a ring 226. To prevent the lower portion of the housing 202surrounding the coil 206 `from providing the effect of a shorted turn orlag coil, this portion of the housing 202 is provided with one or morelongitudinally extending and circumferentially spaced slots 223.

To provide means for cooling the winding 206, this winding is supportedwithin the lower end of the housing 202 spaced from engagement therewithso that a somewhat annular passage or air conveying means 230 isprovided interposed between the housing 202 and the winding 206 throughwhich air can be moved. The passageway or space 230 communicates withthe plurality of slots 228 and with a plurality of openings 232 formedin the lower end of `the member 202. The `winding 206 is held in aposition spaced from the inner wall of the lower portion of the housingmember 202 by a plurality of generally L-shaped spacers 234 which areinterposed between the win-ding 206 and both the inner surface of thelower portion of the housing 202 and the lower surface of the securingring 226.

T-o provide means for driving or impelling air through the passageway orspace 230, the upper end of the armature 210, which is recessed toreduce its mass, is provided with a vane or plunger 236 that isinterposed between a ange 210a on the armature and a collar 23S. Aconical armature return spring 240 is interposed between the collar 238and the upper surface of the ring 226 and normally holds the upper endof the .armature 210 in engagement with a resilient element 242. Thiselement is carried on the cover 220 and is used -to cushion the returnmovement of the :armature 210. The armature 210, the blade 212, and thespring 240 can be removed through the open top of the housing 202 byremoving the closure 220. The winding means 206 and .the spacers 234 canbe removed by removing the locking means 226.

When the tool 200 is operated and the winding 206 is energized, thearmature 210 and the vane or air impelling element 230 move downwardlyagainst the force of the compression spring 240. During this movement,the element 236 impels or forces air drawn into the interior of theupper portion of the housing 202 through a plurality of intake or inletports or openings downwardly through the annular space yor passageway230 and discharges this air through .the slots 228 and the openings 232.Since the slots 228 are very smal-l and can be closed, if desired, by anonconductive material, the bulk of the air is discharged through theopenings 232 and passes substantially completely around and along theentire length of the outer surface of the winding 206. When the winding206 is de-energized, the return spring 240 restores the armature 210 andthe driver blade 212 to the normal position shown in FIG. 4. During thisreturn movement, the suction created by the upward movement of theplunger or vane 236 draws air int-o the space 230 through the opening232. This ow of air during the oppositely directed movements of thearmature 210 incident to each oper-ation of the tool 200 removes theheat generated by .fthe energization of the Winding 206 and maintainsthe operating temperature of the tool 200 within the desired temperaturerange.

In certain applications, such as those in which the components forcontrolling the energiza-tion of the winding 206 are to be carried in oron the handle 204, it is desirable to insure that the heat from thewinding means 206 that is not removed by the cooling means describedabove is not transmitted to the handle 204. Accordingly, a layer or bodyof heat insulating material 246 (FIG. 4) is interposed between theseparate handle 204 andthe housing 202. This heat insulating materialcan be applied to either of the members 202 or 204 or can be formed as agasket that is interposed between these two components during theirassembly. The use of the body 246 of heat insulating material retardsthe transmission of heat generated by .the winding 206 to the handle 204and protects any electronic componen-ts carried therein `from theadverse effects of excessive temperature rises.

As indicated above, the nosepiece assembly 216 and the magazine assembly210 are pivotally mounted relative to the remainder of the tacker 200 toprovide means for maintaining the nosepiece assembly 216 in engagementwith the workpiece when the tool 200 is operated. The rear end of themagazine assembly 218 includes a generally U-shaped element 250 that ispivotally connected to the rear end 204e of the handle 204 by a hinge orpivot assembly indicated generally at 252. To provide means for movablyconnecting the nosepiece assembly 216 with the housing. 202, theassembly 216 includesa nosepiece element 254 defining the drive track211i and having a threaded boss at its upper end on which is threadedlymounted a flanged collar 256. This collar is disposed Within an opening25S inthe lower wall of the element 222. A compression spring 25ddisposed within a circular opening 262 in the boss portion of thenosepiece element 254 engages a lower surface of the member 222 withinthe opening 25S to normally bias the nosepiece assembly 216 and themagazine assembly 218 to` the position illustrated in FIG. 4. ln thisposition, the lip or flange on 'the collar 25o engages the upper edge ofan annular plate 264i that is secured to the member 222 at the lower endof the housing 262.

When the tool Ztl@ is to be operated, the nosepiece assembly 216 isplaced against the workpiece, and the handle 204 and the housing 2(92are moved downwardly against the action of the compression spring 260 tothe position shown in FlG. 6 which is determined by the engagement ofthe upper end of the collar 25o and the boss portion of the nosepieceelement 254 with the lower Wall of the member 222 within the opening258. When the tool 200 is then operated by energizing the winding 2%,the recoil produced by the force required to place the armature 210 inmotion and which results from the oppositely directed components offorce tending to move the armature 210 downwardly and the winding 206 inthe housing 262 upwardly is absorbed by permitting the housing 202 andthe handle 29d to move upwardly in a clockwise direction about thepivotal axis of the assembly 252. During this movement, the compressionspring 260 holds the lower end of the nosepiece assembly 216 inengagement with the workpiece and insures that the fastener supplied bythe magazine 218 is properly driven. The drive track 214 and the blade212 are so proportioned that the" movement of the nosepiece assembly 216does not cause the blade 212 to bind in the drive track 214-.

The movement of the nosepiece assembly 216 and the magazine assembly 218relative to the remainder of the tool 200 can be used to actuate asafety switch means to insure that the nosepiece assembly 216 is inengagement with the workpiece prior to the operation of the tool 259i?.More specifically, a safety switch 270 is secured to the member 222 witha switch actuator element 272 disposed immediately above an uppersurface of the adjacent portion of the magazine assembly 21d. When thetool Ztl@ is placed against the workpiece and depressed so that themagazine assembly 218 and the nosepiece assembly 216 pivot in aclockwise direction about the hinge assembly 252, the actuator element272 is engaged and actuated to operate the switch 276.

Although the present invention has been described with reference toseveral embodiments thereof, it should be understood that numerous othermodifications and embodiments can be devised by those skilled in the artthat will fall within the spirit and scope of the principles of thisinvention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A fastener driving tool comprising a housing structure defining agenerally cylindrical and vertically extending chamber communicatingwith a drive track at its lower end, winding means having an axialopening and an upwardly projecting locating structure at its upper end,said winding means being disposed in the chamber with the axial openingin alignment with the drive track, spider means having a central openingin which the upwardly projecting locating structure on the winding meansis received, detachable fastener means engaging the wall of the chamberand bearing against an outer portion of the spider means to secure thespider means and the winding means in a desired position within thechamber, the engagement of the locating structure by the spider meansholding the winding means in an upright position within the chamberspaced from the inner wall of the housing to provide a generally annularair space surrounding the winding means, said housing structure havingat least one opening communicating with the annular air space adjacentthe winding means, and fastener driving means slidably mounted in thedrive track and including armature means slidably mounted in the axialopening and normally projecting above the upper end of the winding meansinto an upper portion of the chamber above the Winding means and thespider means.

2. rl`he fastener driving tool set forth in claim 1 in which thearmature means is generally cylindrical and of a diameter substantiallyless than the diameter of the upper portion of the chamber in which itis normally disposed, said armature means having a projecting portionadjacent its upper end, and a generally conical resilient spring meansdisposed in the upper end of the chamber having a smaller diameterportion engaging the projecting portion on the armature means and alarger diameter portion supported adjacent the upper end of the Windingmeans.

3. The fastener driving tool set forth in claim 2 in which the housingstructure includes a top opening at the upper end of the upper portionof the chamber having a size to permit the passage of the spring means,spider means, and winding means therethrough; a closure memberdetachably secured to the housing structure to normally close said topopening; said closure member providing a stop for arresting movement ofthe armature means by the spring means, said closure member beingremovable to permit the removal of the spring means and the fastenerdriving means through the top opening and the fastener means beingthereafter removable to permit the spider means and the winding means tobe removed from the housing structure through the top opening.

4. The fastener driving tool set forth in claim 1 in "which the spidermeans comprises a generally circular plate having the central openingfor receiving the upwardly projecting locating structure, the outerdiameter of the plate being no greater than the diameter of the chamber,and in which the detachable fastener means includes a resilient andgenerally C-shaped member, the inner wall of the housing structurehaving a recess in which the C-shaped member is received in a positionbearing against the outer portion of the plate.

5. A fastener driving tool comprising a housing structure defining agenerally cylindrical and vertically extending chamber communicatingwith a drive track at its lower end, said housing structure alsoincluding structure defining a generally circular opening adjacent thelower end of the chamber, winding means having generally concentricupper and lower bossed portions and an axial opening passingtherethrough, said winding means being disposed in the chamber with theaxial opening in alignment with the drive track and with the lowerbossed portion disposed in the circular opening, spider means having acentral opening in which the upper bossed portion of the winding meansis received, detachable fastener means engaging the wall of the chamberand bearing against an outer portion of the spider means to secure thespider means and the winding in a desired position within the chamber,the engagement of the upper and lower bossed portions by the spidermeans and the structure defining the opening serving to hold the windingmeans in an upright position within the chamber spaced from the innerwall of the housing structure to provide a generally annular air spacesurrounding the winding means, said housing structure having at leastone opening communicating with the annular air space adjacent thewinding means, and fastener driving means slidably mounted in the drivetrack and including armature means slidably mounted in the axial openingand normally projecting above the upper end of the winding means into anupper portion i l i 2 of the chamber above the Winding means and thespider References Cited by the Examiner means.

6. The fastener driving tool set forth in claim l in UNITED STATESPATENTS which the spider means includes at least one other open- 757,9914/04 Christmas 310-16 X ing disposed between the cent1-al opening andthe outer 5 864,259 8/07 Bathbun 310-16 X portion of the spider meansfor placing the annular air 1,128,036 2/ 15 Paulero 310-16 X space incommunication with the upper portion of the 1,723,607 8/ 29 DOmHqUSZ310-*16 X chamber disposed above the Winding means, and in which1,837,197 12/31 Berman 310-16 X is provided a generally circularresilient pumping element 2,572,012 10/51 CUTIS. carried by the armaturemeans at the end remote from 10 2,967,302 1/61 LOVGCSS. the Windingmeans and disposed in the upper portion of 3,017,635 1/62 KOeIlDSCke.the chamber, said pumping element being moved toward FOREIGN PATENTS andaway from the winding means as the armature means is operated to moveair through the annular air space to 216983 Y 8/61 Ausma' cool the tool.15 GRANVILLE Y. CUSTER, IR., Primary Examiner.

1. A FASTENER DRIVING TOOL COMPRISING A HOUSING STRUCTURE DEFINING AGENERALLY CYLINDRICAL AND VERTICALLY EXTENDIONG CHAMBER COMMUNICATINGWITH A DRIVE TRACK AT ITS LOWER END, WINDING MEANS HAVING AN AXIALOPENING AND AN UPWARDLY PROJECTING LOCATING STRUCTURE AT ITS UPPER END,SAID WINDING MEANS BEING DISPOSED IN THE CHAMBER WITH THE AXIAL OPENINGIN ALIGNMENT WITH THE DRIVE TRACK, SPIDER MEANS HAVING A CENTRAL OPENINGIN WHICH THE UPWARDLY PROJECTING LOCATING STRUCTURE ON THE WINDING MEANSIS RECEIVED, DETACHABLE FASTENER MEANSF ENGAGING THE WALL OF THE CHAMBERAND BEARING AGAINST AN OUTER PORTION OF THE SPIDER MEANS TO SECURE THESPIDER MEANS AND THE WINDING MEANS IN A DESIRED POSITION WITHIN THECHAMBER, THE ENGAGEMENT OF THE LOCATING STRUCTURE BY THE SPIDER MEANSHOLDING THE WINDING MEANS IN AN UPRIGHT POSITION WITHIN THE CHAMBERSPACED FROM THE INNER WALL OF THE HOUSING TO PROVIDE A GENERALLY ANNULARAIR SPACE SURROUNDING THE WINDING MEANS, SAID HOUSING STRUCTURE HAVINGAT LEAST ONE OPENING COMMUNICATING WITH THE ANNULAR AIR SPACE AD-